Hey Skyfira,
Thank you for your inquiry about these!
All of the building models you listed are a part of the work in progress race, "The Risen", planned to be added to Heaven's Fall. They are a part of a joint project between Glasir and I that is not yet finished. So, essentially, all of your assumptions are correct! They are newer than the rest of the Heaven's Fall content, and will be a part of future updates.
Because the Risen building models are a part of a joint project with Glasir, I checked with him as well. He says he feels it would be alright for you to use them, as long as you give obvious credit for them.